Gene Screening May Lead to More Accurate Prostate Cancer Staging

NEW YORK, NY--(Marketwire - Dec 6, 2011) - Today, doctors use PSA blood tests and Gleason scoring to diagnose and stage prostate cancer in men. Though both are effective in prostate cancer screening, they give doctors and patients a limited picture of the disease's aggressiveness and likelihood to spread. Through the efforts of scientists at the Institute for Advanced Study in Princeton, new prostate cancer staging strategies may be on the horizon.

Researchers evaluated microarray data from patients in Sweden and Memorial Sloan-Kettering Cancer Center in New York to determine how variations in molecular structure link to prostate cancer aggressiveness and mortality. Tumor tissue samples from 281 Swedish watchful-waiting patients and 150 Sloan-Kettering patients were tested independently for mRNA genetic expression patterns.

"What they found," explains Dr. David Samadi, Vice Chairman, Department of Urology, and Chief of Robotics and Minimally Invasive Surgery at The Mount Sinai Medical Center, "are two subtypes of aggressive prostate cancer that were three times more fatal in just a few years. In many of these cases a low or moderate Gleason score was previously assigned." The findings were independent of Gleason scores, indicating this could become a significantly more accurate tool for early prostate cancer staging.

Currently, doctors collect annual PSA blood samples to monitor a man's PSA level velocity over a period of years. A spike in PSA level can indicate the presence of prostate cancer. A biopsy is then performed to evaluate tumor cell patterns and apply a tumor grade Gleason score. In theory, a high score indicates a more aggressive prostate cancer that is more likely to spread and low score indicates a less severe prognosis. But this isn't always the case.

"Unfortunately, too often men with low scores go on to develop advanced prostate cancer," says Dr. Samadi. "We still have a lot to learn. The disease can spread very quickly or take many years to develop; there are just no guarantees, which is why I recommend robotic prostate surgery." Through robotic surgery, Dr. Samadi carefully removes the entire cancerous prostate, effectively eliminating prostate cancer in 97% of his patients.

Dr. Samadi supports the use of PSA tests and Gleason scoring, but is very encouraged by the prospect of improvements in predicting the disease's outcomes. He says, "The sooner we pinpoint survival outcomes, the better we'll be able treat our patients."

The reality of accuracy gaps in current prostate cancer staging and the range of treatment options mean a unique path for each patient. "Careful consideration of a man's age and overall health, along with the recommendations of a prostate cancer expert, should play leading roles," says Dr. Samadi. "Based on the data we have today, men should not rest easy just because they have a low Gleason score."

"I look forward to the day when I can talk to men with more certainty about their unique prostate cancer prognosis. Today, we can diagnose prostate cancer, educate men about risks and recommend the best treatment. In my opinion, we see the best outcomes with robotic prostatectomy surgery," asserts Dr. Samadi.

Scientists have begun prostate cancer gene screening on a larger trial population, but definitive results could take up to fifteen years.